Which of the following chordate characteristics contributes most to the formation of your ears?

• A. Dorsal, hollow nerve cord
• B. Muscular, post-anal tail
• C. Notochord
• D. None of the listed responses is correct.
• E. Pharyngeal clefts

Answer: (E)

Verified step by step guidance

1. Understand the basic characteristics of chordates: Chordates are defined by having a notochord, a dorsal hollow nerve cord, pharyngeal slits or clefts, and a muscular post-anal tail at some point in their life cycle.
2. Identify the function of pharyngeal clefts: In chordates, pharyngeal clefts are structures that can develop into various parts of the body. In aquatic species, they often develop into gills, while in terrestrial vertebrates, they can contribute to structures in the head and neck.
3. Relate pharyngeal clefts to human development: In humans, pharyngeal clefts contribute to the development of the ear and other structures in the head and neck region. Specifically, they play a role in forming parts of the middle ear and the Eustachian tube.
4. Eliminate other options: The dorsal, hollow nerve cord develops into the central nervous system (brain and spinal cord), the notochord provides skeletal support, and the muscular, post-anal tail is a feature that is reduced or absent in many adult chordates, including humans.
5. Conclude with the correct answer: Based on the developmental role of pharyngeal clefts in forming ear structures, the characteristic that contributes most to the formation of human ears is the pharyngeal clefts.